Propelling vessels by steam-turbines.



No. 7I6,468.

Patented Dac. 23, |902. C. A. PARSONS. PBOPELLING VESSELS BY STEAM TUHBINES.

(Application led Jan. 26, 1897.)

(No Model.)

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UNTTED STATES PATENT OFFICE.

CHARLES ALGERNON PARSONS, OF NEWCASTLE-UPON-TYNE, ENGLAND.

PROPELLING VESSELS BY STEAVi-TURBINES.

SPECIFICATION forming part of Letters Patent No. 716,468, dated December 23. 1902.

Application led JanuaryZ, 1897. Serial No. 620,719. (No model.)

To ctZZ whom t may concern:

. Be it known that I, CHARLES ALGERNON PARSONS, engineer, a citizen of Great Britain, residing at Heaton Vorks, Newcastle-upon- Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in Propelling Vessels by Steam-Turbines, of which the following is a speciiication.

My invention relates to vessels propelled by steam-turbines; and my object is to obviate certain dificulties which I have experienced in applying steam-turbines to marine purposes.

I have found that when a steam-turbine constructed according to any of my wellknown types is applied to working a screwpropeller directly the high speed of the turbine necessitates'a diameter of screw-propeller which is rather too small to provide sufficient blade area to absorb the power of the engine in propelling the Vessel with a high efficiency and that sometimes under such condition the efficiency is reduced by the formation of vacuum behind the blades of the propeller.

I arrange two or more screw propeller shafts, to each of which I couple a steam-turbine, which turbines are coupled by pipes and valves, so as to cause the steam to pass through them in series or in multiple series. By this arrangement the steam passes from turbine to turbine and its expansion is completed in the series. I thus divide the total power available among two or three or even more screw-propeller shafts and use a compound tu rbine,which has a distinct advantage over one large motor in that its members or turbines are severally more rigid in construction than the one large motor. They permit of greater refinements of construction, and lower angular speeds may also be adopted without affectingthe economicalconsumption of the steam.

I do notwish to limit myself to coupling each turbine separately to a screw-shaft.

The turbines I adopt may be of any known type; but I prefer my well-known turbins with or without steamebalancing arrangements for the screw thrust. The turbines may be fitted with reversing-gear, if desired. Superheaters or steam-driers in the main steam-pipe or in the connecting-pipes between the motors may also be used. I may also fit between the motors suitable by-passes and Valves to secure their joint or independent Working.

Referring to the accompanying sheet of drawings, illustrating one method of carrying my invention into eect, Figure lis a longitudinal section through part of a steam vessel, showing my turbine as applied to multiple propeller-shafts; and Fig. 2 is the corresponding plan.

In the embodiment of my invention shown I use three turbines, through which the steam passes in series, the three turbines being coupled to three propeller-shafts. The high pressure steam is admitted to the high-pressure turbine C2 by the steam-inlet pipe L. After passing through the turbine C2 it is conducted by the pipe D .to the intermediate turbine C, whence it passes to the low-pressure turbine C through -any suitable pipe, as that shown at OX, and then the steam passes to the surface condenser by the large pipe F. The turbine C is coupled to the propellershaft A, which shaft carries three propellers B. The turbine O is coupled to the shaft A', which carries three propellers B', and the turbine C2 is coupled to the shaft A2, which carries three propellers B2. The furnace-forced draft-fan E is also driven from the low-pressure turbine. A reciprocating air-pump G, Fig. l, is adopted for the condenser, and it is operated by the small reciprocating steamengine H.

I have found that at the high speed necessary to obtain economy in steam consumption from a turbine and propellers on a single shaft the propellers formed an almost continuous vacuum behind the blade, and thus led to an enormous waste of power.

the turbine-spindle by arranging in a vessel a steam-turbine divided into three portions, each portion rotating a separate shaft having thereon a propeller. By 'this arrangement Recognizing this, I sought to reduce the speed of at a lower speed than was otherwise possible. By combining with these three shafts screwpropellers in sufficient numbers of small diameter and yet in their sum of great blade area I obtained economical propulsion and an absence of vacuum loss. By my invention I am enabled to run the three shafts at a lower speed than can be done with one shaft. Further, it is practically impossible to greatly reduce speed by increasing the number of rows of blades upon one shaft. If the motor is lengthened, so as to interpose, say, two or three times the number of rows of blades between the steam entry and eX- haust, so as to get a slower velocity of steam and permit of a slower rate of rotation consistent with good steam economy, it is found that the lengthening of the shaft causes so much spring as to require greatly-increased clearance between the edges of the blades and the casing and the edges of the fixed and moving blades. The economy obtained in -is obtained and a steam-supply, the said turbines being connected thereto in series whereby the steam passes through the turbines in series and the whole expansive force is utilized and distributed to the several propellers, substantially as described.

In witness whereof I have hereunto set my hand in presence of two witnesses.

CHARLES ALGERNON PARSONS.

Witnesses: I

THOMAS JAMESON, THOMAS RODHAM HUTCHINsoN. 

